Top seeded or not, Lu seems to really like Challengers. When other players at his level are contesting ATP 250s or Masters-level qualifying draws, the Taiwanese #1 is demonstrating his dominance of the minor leagues. And it’s working: In large part thanks to titles in places such as Shanghai, Ningbo, Seoul, and Singapore, he has kept his ranking in the top 100 for about three years.

Lu’s combination of consistency near the top and Challenger preference is unusual but not unique. He is one of 14 players who, since 2007, have played at least 20 Challenger events while ranked inside the top 100. He is, however, the most extreme member of the group. This week’s Guadalajara event will be his 40th Challenger as a member of the top 100. Dudi Sela, also in Guadalajara but currently outside the top 100, has played 31 while part of that more elite club.

While Sela has a longer track record (and a bit more success) on dirt, his current preferences are very similar. Given the choice between a hard-court Challenger and anything on clay, and he’ll take the Challenger. While there aren’t as many tour-level events on clay as Rafael Nadal might like, there are enough to keep Lu and Sela on the lower circuit for several months of the year.

Most of the other players who rack up extensive Challenger records while ranked in the top 100 have the opposite preference. Filippo Volandri and Ruben Ramirez Hidalgo are the most extreme. While ranked that high, each has only played three ATP qualifying events, despite entering 29 and 27 Challenger events, respectively, since 2007. (RRH’s career figures are higher; I’m using the time span since 2007 because my qualifying database only goes back that far.)

Here’s the list of all players who have contested 20 or more Challengers while ranked in the top 100 since 2007, along with the number of ATP qualifying draws they entered while in the top 100 and the rate at which they chose Challengers out of these two options.

I have heard that Lu gets 3000$ per ranking point (the Japanese players get 200$ per ranking point for sure, as Amir Weintraub has said in an interview). That can explains his choices a lot.
About Sela, last year he has gone to clay tounaments while ranked in the top70, and he admitted himself it was a huge mistake. LA and Washintgton could have been a great opportunity for hime, if he was ranked high enough to get in.